First S-RAMP (STEP Results, Analysis, and Modelling Phase of the Solar-Terrestrial Energy Program).
Sapporo, Japan, 2-6 October, 2000.

The first international S-RAMP symposium consisted of 19 sub-symposia and three workshops. The S-RAMP project has been promoted by SCOSTEP (Scientific Committee on Solar-Terrestrial Physics) in 1998-2002 in order to consolidate and integrate results from the many disparate STEP (Solar-Terrestrial Energy Program) campaigns in 1990-1997.

The SRAMP symposium was sponsored by the Ministry of Education, Science, Sports and Culture, Japan (Monbusho) and SCOSTEP ("http://www.ngdc.noaa.gov/stp/SCOSTEP/scostep.html").

 

Symposium S17: The middle atmosphere including response to forcing from above.

Marvin Geller and Toshitaka Tsuda (mgeller@notes.cc.sunysb.edu).

This symposium was devoted to the dynamics and chemistry of the middle atmosphere, with particular emphasis on wave forcing, having their sources in the troposphere and to chemical changes from natural and anthropogenic causes. Because the middle atmosphere is also subject to forcing from the variable sun and energetic particle effects, the chemistry, energetics, and dynamics of the middle atmosphere in response to these forcings were also key subjects of this symposium.

The main topics in dynamics were radar/optical/in-situ observations, modelling and theory of the general circulation, generation and propagation of various atmospheric waves, and their interactions and instabilities. Topics in chemistry included observational analyses, laboratory and modelling of gas phase and heterogeneous photochemical processes, as well as studies of transport and mixing of minor constituents. The coupling between chemistry, radiation and dynamics was also an important subject of this symposium.

A total of 41 papers were presented: 23 presentations, including seven solicited papers, were given orally in two sessions on October 3 and 5, and 18 were displayed as posters. The first oral session treated tropospheric processes, where M. A. Geller talked on the QBO and ENSO influences on the tropical cold point tropopause, followed by a summary report of the SPARC/SOWER campaigns in 1998-2000 by F. Hasebe. Then, in a session on chemistry and transport, S. Hayashida described the behaviour of the polar stratospheric clouds (PSCs) observed from space, and M. Takahashi showed the results on ozone variations seen in chemical climate models.

In session on the processes in the Mesosphere and Lower Thermosphere (MLT) region, R. A. Goldberg talked on a study of polar summer mesosphere with rocket, radar and lidar (DROPS program). N. J. Mitchell discussed the coupling of tide and planetary waves, and J. F. Kafkalidis described the planetary scale variations in the nightglow structures seen by UARS/HRDI satellite.

 

Symposium S18: Solar variability effects upon the lower atmosphere and climate

Lon Hood and John Austin (lon@lpl.arizona.edu)

Most of the papers were observationally based, with a strong emphasis, on the interaction of solar cycle forcing with that by the equatorial wind QBO.

K. Labitzke showed updated results from the data set compiled at the Free University of Berlin, which now indicate an 11-year solar signal in lower stratospheric geopotential height extending over at least 4 solar cycles.

Additional analysis of the US National Centre for Environmental Prediction (NCEP) data set, which includes the Southern Hemisphere, was also presented. K. Mohanakumar reported evidence for an influence of the 11-year cycle on temperature in the mesosphere (6-8 % per 100 units of 10.7 cm solar flux) and in the troposphere (1-2% per 100 units) using a combination of radiosonde data, rocket data, and the NCEP reanalysis data. H. Nakane also applied the NCEP reanalysis data from 1959 to 1997 to investigate properties of the northern polar vortex. It was found that properties of the vortex, including strength, duration, radius, and stability, depended on the phase of the 11-year solar cycle as well as that of the QBO. A similar theme was pursued by Y. Naito who showed that the "Holton-Tan Oscillation" in which polar temperatures are forced entirely by the QBO has a different phase dependence under solar maximum conditions as compared to solar minimum conditions. M. Salby suggested that some aspects of the QBO itself (equatorial westerlies below 30 hPa and equatorial easterlies above 30 hPa) may vary slightly with the 11-year solar cycle.

J. Austin presented the results of general circulation modelling in which the primary forcing is variations of several percent in the UV part of the solar spectrum. Comparisons of the model response on the solar cycle time scale with satellite observations of ozone and temperature changes were presented. M. Takahashi presented a range of results from the CCSR/NIES climate model. These included investigations of the 11-year solar cycle, which gave very similar results to those of Austin. In particular, the model results were significant improvements over 2D models in the lower stratosphere, while a discrepancy remains in the upper stratosphere. Simulations with the Berlin climate model had not commenced by the time of the meeting but the model was outlined in a poster display.

A number of other potentially important issues were addressed. In a plenary lecture preceding the symposium, E. Friis-Christensen suggested that Galactic cosmic ray (GCR) fluxes, which are modulated by the 11-year solar magnetic activity cycle, may be an additional contributor to solar forcing of climate through effects on cloud nucleation processes. K. Georgieva pointed out that the effects of GCR's on terrestrial climate may depend on whether the northern or the southern solar hemisphere is more magnetically active. O. Troshichev noted that an empirical separation of energetic particle effects on the middle and lower atmosphere from those of spectral irradiance variability may be facilitated by analysing data from the polar night. He presented correlative evidence for effects of short-term (days to weeks) GCR variability on pressure in the stratosphere and troposphere at the Vostok station in Antarctica. K. Boyarchuk pointed out that the solar output varies on a number of time scales, including a small-amplitude periodicity near the QBO period, and that this periodicity may influence GCR access to the atmosphere on the same time scale. D. Knipp investigated the heat budget above the stratosphere and showed that solar UV radiation accounts for 70-80 % of the heating while auroral zone currents and particle deposition account for another 15-25 %. T. Kuznetsova analysed terrestrial Carbon 14 data (an inverse proxy for solar activity through effects on GCR fluxes reaching the ground) for a 4500-year period and discussed two maxima, one of which coincides with the Maunder sunspot minimum. She suggested that global temperature may correlate inversely with Carbon 14 and that extrapolation of the available record using Fourier harmonics provide a forecast of climate change. B. Zieger investigated the behaviour of Schumann resonances (SR) in the Earth's ionosphere which are associated with lightning discharges.